The invention relates to a method of manufacturing an optical grating. In the method, the starting material has a surface which is provided with equidistant grooves. In one embodiment of the method a metal body is provided with grooves, for example by scratching it with a diamond.
The grooved starting material is then used as a jig to make gratings. For example, the jig may be used to form impressions in a layer of lacquer on a supporting glass plate. The lacquer layer is then covered with a metal layer.
The regularity and the shape of the grooves determine the quality of the grating.
The disadvantages of the known method are, in particular, that the production method is expensive and that the layer of lacquer is vulnerable to damage.
Gratings are generally used in scientific instruments which are not mass produced and in which the cost is a comparatively small factor. The gratings can generally be custom made to the requirements of the instrument. However, when used on a large scale, for example in telecommunicatons, the gratings must be cheap and sturdy.